The Third Small Astronomy Satellite (SAS-3)

The third US Small Astronomy Satellite (SAS-3)
was launched in May 1975, with 3 major scientific objectives: 1)
determine bright X-ray source locations to an accuracy of 15
arcseconds; 2) study selected sources over the energy range
0.1-55 keV; and 3) continuously search the sky for X-ray novae,
flares, and other transient phenomena.
It was a spinning satellite with pointing capability.

Mission Characteristics

Lifetime : May 1975 - Apr 1979
Energy Range : 0.1-60 keV
Payload :
There are four X-ray experiments on SAS-3 that all used proportional
counters as detectors with different collimating system.
The experiments were not co-aligned.

Modulation collimators (2-11 keV)

Slat and Tube collimators (1 up to 60keV)

Low-energy detector system
0.15-1.0 keV, 2.9° FOV

Science Highlights:

Discovery of a dozen X-ray burst sources among which
the Rapid Burster

First discovery of X-ray from an highly magnetic WD binary
system, AM Her